Canada will soon have two more vaccines to combat the COVID-19 virus.
Health Canada has approved the AstraZeneca vaccine along with a related shot by the Serum Institue of India.
Dr. Supriya Sharma, a senior medical advisor with Health Canada, provided details about the vaccines during a briefing Friday morning.
Sharma said unlike the Pfizer/BioNTech and Moderna vaccines, which are m-R-N-A based, these new vaccines are viral-vector-based.
“Viral-vector vaccines use a harmless modified version of a different virus, the vector, to deliver instructions to our cells,” said Sharma. “The cells begin to make proteins from the virus that causes COVID-19, which then prompts the body to develop an immune response.”
Sharma said the virus used in these vaccines are adenoviruses, which have been used in vaccines for decades.
She said the adenoviruses can cause common cold-like symptoms but do not cause illness.
“These are two-dose vaccines with the second dose being given between four and 12 weeks after the first. Evidence suggests that efficacy increases with longer dosing intervals,” said Sharma.
Sharma said the vaccines are about 62 per cent effective in preventing symptomatic cases of COVID-19, much lower than the Pfizer/BioNTech and Moderna vaccines.
But she said there is “emerging, promising evidence” that is beginning to be reported from real-world use of the vaccine.
Sharma said two other vaccine submissions remain under review by Health Canada.
